A train car with a mass of 2.5 x 104 kg traveling north at 1.8 m/s collides and joins with another train car with a mass of 3.5 x 104 kg that was traveling south at 0.78 m/s. What is the velocity (magnitude and direction) of the joined train cars after the collision.

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?

Convection occurs when thermal energy is transferred by the movement of

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600